1. Field of the Invention
This invention pertains broadly to the field of communications. More particularly, the invention pertains to communication receivers. In still greater particularity, but without limitation thereto, the invention relates to a communications system and method for cancelling high power out-of-band pulse interference signals.
2. Description of the Prior Art
As airwave communications become more and more crowded, it is common for communication receivers to pick up undesirable transmissions. This is particularly the case where various receivers and transmitters are located in close proximity as well as where communication channels are close in frequency. In cases in which alarm or counter circuits are used in conjunction with receiver systems, the reception of undesired transmissions can result in false alarms or inaccurate counts.
Where radar systems are used, reception of undesired transmissions can lead radar operators to believe that objects exist where they do not actually exist. The interfering signals can further mask the location of objects within the radar's range, thus providing an apparently free path for objects to be guided through. In either case lives may be endangered and property may be jeopardized.
In many cases the source of interfering signals lies with transmitters operating close to or on a receiver's operating frequency. In other cases these interfering signals are caused by transmitters broadcasting transient pulses having frequency components that fall within the frequency range of the monitoring receiver. Further, radar and TV transmitters often broadcast signals of such high signal strength or power that normal reception on nearby receivers becomes masked or obscured.